Bald Eagle

Bald Eagle, Roger Inghram Photo

(Haliaeetus leucocephalus)

Physical Characteristics: 28-40 inch body length, wingspan of 5-7 feet, weighing 5-15 pounds. Head and wedge-shaped plumage are white, yellow beak and feet. Legs are feather-free, toes are short with large talons. The talon on the hind toe is a cunning evolution, designed to fatally pierce prey while held immobile by the front toes. Plumage of immature bald eagles is brown speckled with white, which it retains until it reaches sexual maturity. In flight, can reach speeds of 40-50 mph, with a dive speed of up to 100 mph.

Diet: Opportunistic feeders, a diet largely of fish, specifically trout and salmon in the Pacific Northwest. Rely on scavenging carrion, especially in the winter, from small mammals to ungulates. Mammalian prey includes rabbits, raccoons, muskrats, beavers, and deer fawns. Birds and amphibians also preyed on.

Habitat: Prefers large bodies of water, needs old-growth and mature conifer and hardwood trees for nesting, perching, and roosting. Selected trees must have good visibility, open structure, and proximity to prey. Also important is an abundance of comparatively large trees surrounding the body of water. Is extremely sensitive to human activity, is usually found no less than 1-mile away from even low-density human disturbance.

Range: Natural range covers most of North America. Is partially migratory, depending on location and availability of food, and may congregate in certain locations in winter such as a river where salmon spawning is occurring. In Clearwater Country, bald eagles have been known to inhabit the Meadow Creek and John Day areas.

Reproduction: Bald eagles often return to their birth place. It is thought that pairs breed for life, though if one dies or a pair fails to reproduce after several attempts they may split and look for new mates. Mating is a flight display including swoops, cartwheels, chases, and locking talons to dive dizzyingly, letting go at the last moment to avoid hitting the ground. Mating season is anywhere from late September to early April; the female lays her first egg 5-10 days after mating. Both the male and female help build the nest out of branches—which can be enormous—and add to and fix it every year. There are 1-3 eggs in a clutch, which incubate for about 35 days; the parents take turns incubating, hunting for food, and looking for nesting material. Average lifespan in the wild is twenty years.

Threats: It is estimated that in the 1700s, bald eagle numbers were 300,000-500,000. In the late 20th century, however, they teetered on the brink of extirpation in the lower United States, with total breeding pairs estimated at about 500. This was in part due to the widespread use of the pesticide DDT, which weakened eggshells so much that they would crush under the weight of the adult eagles. Populations have since recovered drastically, though illegal hunting of eagles, habitat loss, and poisoning from ingesting lead shot remain threats to these majestic birds. They have been officially delisted from both the endangered and threatened species lists.

Miscellaneous: Bald eagle size and age varies with location, following an eco-geographic rule asserting that species size increases positively with distance from the equator. For example, the smallest bald eagle specimens are found in Florida, where they may be less than half the length and weight of the largest specimens found in Alaska. Interestingly, females are consistently 25 percent larger than males. Before the bald eagle was the iconic bird symbol of the United States federal government, it has long figured prominently in some Native American cultures. Its feathers and talons are central to many spiritual and religious customs, and the birds themselves considered spiritual messengers between humanity and god or gods in some cultures.